Section
5
MAINTENANCE
5-1. INTRODUCTION
This section contains per iodic maintenance and perform ance test pr ocedures for the Multicarrier
Cellular Amplifier System. It also contains a list of test equipment required to perform the
identified tasks.
NOTE
Check your sales order and equipment warranty
before attempting to service or repair the unit. Do
not break the seals on equipm ent under warranty or
the warranty will be null and void. Do not return
equipment for warranty or repair service until proper
shipping instructions are received from the factory.
5-2. PERIODIC MAINTENANCE
Periodic maintenance requirem ents are listed in Table 5-1. Table 5-1 also lists the inter vals at
which the tasks should be performed.
WARNING
Wear proper eye protection to avoid
eye injury when using compressed air.
Table 5-1. Periodic Maintenance
TASK INTERVAL ACTION
Cleaning
Air Vents 30 Days Inspect and clean per para. 5-4.
Inspection
Cables and
Connectors
Performance Tests
5-3. TEST EQUIPMENT REQUIRED FOR TEST
Test equipment required to test the amplifier system is listed in Table 5-2. Equivalent test
equipment may be substituted for any item; k eep in mind that a thermistor type power meter is
required.
All RF test equipment must be calibrated to 0.05 dB
resolution. Any deviation from the nominal attenuation m ust
be accounted for and factored into all output readings.
12 Months Inspect signal and power cables
for frayed insulation. Check RF
connectors to be sure that they are
tight.
12 Months Perform annual test per para. 5-5.
NOTE
044-05055 Rev. A 5-1
Table 5-2. Test Equipment Required
NOMENCLATURE MANUFACTURER MODEL
Signal Generator RDL IMD-801D-03A
30 dB Attenuator, 500 Watt Weinschel Corp. 53-30-34
10 dB Attenuator, 20 Watt
Tenuline
(2 each)
Spectrum Analyzer H.P. 8560E
Coax Directional Coupler H.P. 778D
Power Meter/Sensor H.P. 437B/8481A
Network Analyzer H.P. 8753C
Current Probe
5-4. CLEANING AIR INLETS/OUTLETS
The air inlets and outlets should be cleaned every 30 days. If the equipment is operated in a
severe dust environment, they should be cleaned more often as necessary. Turn off DC power
source before rem oving fans. If dust and dirt are allowed to accumulate, the cooling eff iciency
may be diminished. Using either compressed air or a brus h with soft bristles , loosen and rem ove
accumulated dust and dirt from the air inlet panels.
5-5. PERFORMANCE TEST
Performance testing should be conducted every 12 months to ensure that the amplifier system
meets the operational specif ications listed in table 5-3. Also verify system perf ormanc e after any
amplifier m odule is replaced in the field. The test equipment required to perform the testing is
listed in table 5-2, and the test setup is shown in figure 5-1.
NOTE
The frequencies used in this test are typical for an am plifier with
a 25 MHz band from 869 MHz to 894 MHz. Select evenly spaced
F1, F2, F3, and F4 frequencies that cover the instantaneous
bandwidth of your system.
5-5.1. AMPLIFIER SYSTEM PERFORMANCE TEST.
This test is applicable to the MCR20XX Series (NTL107AC) subrack with two plug-in G3X-800
Series (NTL107AA) amplifier modules. To perform the test, proceed as follows:
1. Connect test equipment to the subrack as shown in figure 5-1.
NOTE
Do not apply any RF signals at this time.
2. Turn on signal generator and set frequency F1 to 880 MHz, F2 to 883 MHz, F3 to 886
MHz, and F4 to 889 MHz. Adjust each signal generator output so that the sum power
output from all four signal generators equals -4 dBm at the output of the 4-way combiner.
044-05055 Rev. A 5-2
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